A navigation system, typically a vehicle navigation system, performs travel guidance for enabling a user to easily travel to a selected destination. Such a navigation system detects the position of the user or a vehicle having the navigation system, reads out map data pertaining to an area from a data storage medium, for example, a CD-ROM (compact disk read-only memory) or a DVD (digital videodisc) or a hard disc. The current user (vehicle) position is determined by a combination of a self-contained navigation sensors (distance traveled sensor, bearing sensor, etc.) and a global positioning system (GPS) satellite.
FIGS. 1A–1H show an example of overall procedure and screen display involved in the navigation system. FIG. 1A shows an example of locator map screen of the navigation system when the destination is not specified. Typically, the navigation system displays a street on which the vehicle (current vehicle position VP) is running on a map image and a name of the street. Other information such as a north pointer NP, a map scale and a current time may also be illustrated on the display screen. The navigation system does not perform the route guidance function until a destination is specified.
FIGS. 1B–1D show an example of process for specifying a destination in the navigation system. A main menu screen such as shown in FIG. 1B displays menu items including a “Destination” menu for entering the destination. When selecting “Destination”, the navigation system displays a “Find Destination by” screen as shown in FIG. 1C for specifying an input method for selecting the destination. The “Find Destination By” screen lists various methods for selecting the destination including “Address” for specifying the city and address of the destination, “Intersection” for specifying the names of two streets which intersect with one another, and “Point of Interest” (POI) for selecting the programmed destination based on the name, category or telephone number. Other methods in the “Find Destination by” screen include “Recent Route” for specifying the destination based on the recent history of destinations saved in the navigation system, and “Address Book” for selecting the address of the destination out of the prescribed address list stored in the system.
When selecting, for example, the “Point of Interest” method in FIG. 1C, the navigation system displays selection methods of point of interest (POI) either by “Place Name” or “Place Type” in FIG. 1D. The “Place Name” is to specify a name of POI, and the “Place Type” is to specify a category of POI. If the “Place Name” is selected in FIG. 1D, the navigation system shows an “Enter Place Name” screen such as shown in FIG. 1E. The screen of FIG. 1E is basically a keyboard for inputting the name in an input box on the monitor screen. The user inputs the name of the desired POI in the input box through the keyboard.
FIG. 1F shows a “Confirm Route” screen of the navigation system for confirming the destination. In this example, the “Confirm Route” screen lists the name, address and phone number of the destination (i.e., the POI specified by the user). If this is the correct destination, the user enters an “OK to Proceed” key to proceed to the next procedure.
In FIG. 1G, the navigation system calculates and determines a guided route to the destination, i.e., the selected POI. The navigation system determines a route to the destination based on, for example, the shortest way to reach the destination, the route using as much freeway as practical or the route without using toll road, and the like. In this example, the navigation system displays a progress scale of the calculation of the route. After determining the guided route, the navigation system starts the route guidance as shown in FIG. 1H. Typically, the navigation system shows the intersection which is highlighted to show the next turn and a direction of the turn. Such route guidance by the navigation system is also given by voice instructions.
As noted above, in setting a destination, the user may select a particular destination by selecting, for example, a point of interest (POI) on a display or by inputting a particular destination by using a keyboard screen display as noted above. In some cases, it is beneficial to search a particular destination within a specific area. For example, a user may want to dine at a restaurant within a particular area when he knows that the traffic condition is favorable in that area.
In the conventional navigation system, a function is provided that allows the user to limit the search of points of interest within a particular city. However, it could not accommodate the situation where the user wish to search an area that crosses a multiplicity of cities or any desired area. In many cases, an area of a city is too large to effectively limit the area to be searched or too small to effectively retrieve desired information. Moreover, the user may wish to know whether he has entered into a particular area as opposed to reaching a particular point.
Accordingly, there is a need for a method and apparatus for use with a navigation system that allows the user to freely specify and modify an area for effectively retrieving points of interest (POIs) information or other information within the specified area.